Download Item:

Abstract:

Body size and metabolic rate both fundamentally constrain how species interact with their environment,
and hence ultimately affect their niche. While many mechanisms leading to these constraints
have been explored, their effects on the resolution at which temporal information is perceived have
been largely overlooked. The visual system acts as a gateway to the dynamic environment and the
relative resolution at which organisms are able to acquire and process visual information is likely to
restrict their ability to interact with events around them. As both smaller size and higher metabolic
rates should facilitate rapid behavioural responses, we hypothesized that these traits would favour
perception of temporal change over finer timescales. Using critical flicker fusion frequency, the lowest
frequency of flashing at which a flickering light source is perceived as constant, as a measure of the
maximum rate of temporal information processing in the visual system, we carried out a phylogenetic
comparative analysis of a wide range of vertebrates that supported this hypothesis. Our results have
implications for the evolution of signalling systems and predatoreprey interactions, and, combined
with the strong influence that both body mass and metabolism have on a species? ecological niche,
suggest that time perception may constitute an important and overlooked dimension of niche
differentiation.